1. Field of the Invention
The present invention relates to a chipping-resisting paint coating method capable of preventing an automobile from having its paint film chipped or damaged by the gravel spread over the road (as will be called the "stone chipping"), to maintain the satisfactory appearance and quality of the automobile body at all times.
2. Prior Art
If an automobile runs in winter on an unpaved road of a briny land, its body is frequently dented at its hood leading end, its tire housing or its periphery by the pebbles popped up by the wheels. The dented portion will be corroded, if left untreated, as a result of the chipping. Thus, the painted surface of the car body has to be protected against the so-called "chipping damage", and a variety of means have been proposed in the prior art. In Japanese Patent Laid-Open No. 171681, for example, there is described a coating method of coating the top paint of the car body at its stone chipping susceptible portion with an urethane clear paint which contains specified amounts of polyester resin, melamine resin and cellulose acetate butyrate resin. According to the disclosure of this coating method, the urethane clear paint is baked and set to protect the top and lower paint layers of and set to protect the top and lower paint layers of the car body with the set coating film to provide a satisfactory appearance.
In the prior art exemplified above, however, the top coat has its dents left, if it is subjected to the chipping damage as the time elapses, on the set coating film of the urethane clear paint even if the top paint film is protected by the set coating film and if the damage should not reach the top paint. Thus, the method of the prior art has a defect that the appearance is deteriorated. Still the worse, the urethane clear coating film, which was once baked and set, is characteristically difficult to strip or remove from the top paint film so that it cannot be cleared of the residing dents. Thus, another difficulty is that the coating film cannot restore, if once damaged, its original appearance.